As a known facsimile apparatus connectable with a data processing terminal, such as a personal computer, there is a facsimile apparatus connected with the terminal through a two-way parallel port (compliant with IEEE 1284) interface, e.g., Centronics or the like, or a Universal Serial Bus (USB) interface, as disclosed in Japanese Patent Application Laid-Open No. 7-288625.
In an image processing system constructed with the aforementioned facsimile apparatus and data processing terminal, as a connection form between the facsimile apparatus and data processing terminal, a single logical interface is assigned to a single physical interface.
A brief construction of an image processing apparatus 1100 which constitutes a conventional image processing system is described in detail with reference to FIG. 15.
In the image processing apparatus 1100, a CPU 1101 serving as a system control unit controls the entire image processing apparatus 1100. ROM 1102 stores control programs and an incorporated operating system (OS) program or the like, which are executed by the CPU 1101. Each of the control programs stored in the ROM 1102 executes software controlling, e.g., scheduling, task switch, interruption and so on, under the control of the incorporated OS stored in the ROM 1102, thereby a multi-task function including print control, read control, and communication control is realized.
RAM 1103, configured with SRAM (static RAM) which requires a back-up power source, or the like, keeps stored data by receiving power supply from a primary battery (not shown) for data back-up. The RAM 1103 stores program control variables or the like which must not be lost, and setting values registered by an operator as well as control data of the image processing apparatus 1100 and so on, and includes a buffer area for various works. Image memory 1104, configured with DRAM (dynamic RAM) or the like, stores image data to be handled in the image processing apparatus 1100 and status information obtained from a recording unit 1115. Further, a part of the image memory 1104 is secured as a work area for software processing.
A data conversion unit 1105 performs image data conversion, such as interpretation of a page description language (PDL) or the like, computer graphics (CG) development of character data and so on.
A reading control unit 1106 performs various image processing, e.g., binarization, halftone processing or the like, on an image signal obtained by a reading unit 1107, which optically reads an original document with the use of a contact image sensor (CIS) and converts the read data to electric image data, through an image processing control unit (not shown) and outputs high-definition image data. Note that the reading control unit 1106 and the reading unit 1107 are adaptable to both a sheet-reading control method of performing reading while conveying an original document with the CIS fixed at a predetermined position, and a book-reading control method of scanning an original document placed on a platen while moving the CIS.
An operation display unit 1108, including numeric value input keys, character input keys, one-touch telephone number keys, mode setting keys, an OK key, a cancel key and so on, is constructed with an operation unit for a user to decide image transmission destination data or to perform registration operation of setting data, various keys, a light-emitting diode (LED), and a liquid crystal display (LCD). The operation display unit 1108 displays operator's various input operations and an operation state or status of the image processing apparatus 1100.
A communication control unit 1109 is constructed with a modulator-demodulator (MODEM), a network control unit (NCU) and so on. The communication control unit 1109 is connected with an analogue communication line (PSTN) 1131 to perform, for instance, communication control according to the T30 protocol, or line control such as call out and call in of the communication line.
A resolution conversion processing unit 1110 performs resolution conversion control, such as millimeter-to-inch resolution conversion of image data. Note that in the resolution conversion processing unit 1110, enlargement/reduction processing of image data is possible. A coding/decoding processing unit 1111 performs coding/decoding processing on image data (non-compressed or compressed with MH, MR, MMR, JBIG, JPEG or the like) handled by the image processing apparatus 1100, or performs enlargement/reduction processing.
A print control unit 1112 performs various image processing, such as smoothing, print density correction, color correction and so on, on image data subjected to printing through an image processing control unit (not shown), and thus converts the data to high-definition image data to be outputted to an IEEE 1284 host control unit 1114 (to be described later).
A USB function control unit 1113, which performs communication control of a USB interface, performs protocol control according to the USB communication standard, converts data transmitted from a USB control task executed by the CPU 1101 into a packet, and transmits the USB packet to an external data processing terminal (not shown), or inversely, converts a USB packet from an external data processing terminal into data and transmit the data to the CPU 1101. The USB communication standard realizes high-speed two-way data communication, and allows a plurality of hubs or functions (slaves) to connect with one host (master). The USB function control unit 113 serves as a function in the USB communication.
The IEEE 1284 host control unit 1114 is a control unit for performing communication according to a protocol designated by a compatibility mode of the IEEE 1284 communication standard. The compatibility mode of the IEEE 1284 communication standard, capable of one-way data communication, can connect one host (master) with one peripheral (slave). The IEEE 1284 host control unit 1114 serves as the host in the IEEE 1284 communication, and transmits only print data to the printing unit 1115.
The printing unit 1115, which is a printing device configured with a laser beam printer, inkjet printer or the like, prints color image data or monochrome image data on a printing material. The printing unit 1115 communicates with the IEEE 1284 host control unit 1114 according to a protocol designated by the compatibility mode of the IEEE 1284 communication standard. Particularly the printing unit 1115 serves as the peripheral. In the IEEE 1284 communication, the printing unit 1115 receives print data from the IEEE 1284 host control unit 1114. Meanwhile, the printing unit 1115 performs asynchronous serial interface (UART) communication with a serial I/F control unit 1116 (to be described later). In the asynchronous serial interface communication, the printing unit 1115 receives a command from or transmits print status data to the serial I/F control unit 1116.
The serial I/F control unit 1116 is a control unit for performing asynchronous serial interface communication. Asynchronous serial interface communication is low-speed data communication capable of full-duplex transmission. The serial I/F control unit 1116 transmits a command to or receives print status data from the printing unit 1115.
The aforementioned components 1101 to 1106, 1108 to 1114 and 1116 are connected to each other through a CPU bus 1121 controlled by the CPU 1101.
However, in the above-described conventional image processing system, since only one logical interface is assigned to a single physical interface, there is a great problem in a case where a data processing terminal controls a multi-function facsimile apparatus integrally having a plurality of functions, such as a printer, scanner, facsimile communication and so forth. More specifically, it is impossible to simultaneously operate the plurality of functions, thus unable to sufficiently take advantage of the merit of the multi-function facsimile apparatus.
To force the simultaneous operation of the plurality of functions, the following workload is required. More specifically, in a data processing terminal, it is necessary to add header information specifying a function, such as a printer, scanner, facsimile communication or the like, to the head of an intended control command, edit and packet the data, and transmit the packeted data to the multi-function facsimile apparatus. Therefore, there are great problems in terms of an alteration workload of a driver which is installed in a data processing terminal, complexity of the control, and a throughput.
Moreover, in the multi-function facsimile apparatus which receives packeted data from the data processing terminal, it is necessary to analyze the packeted data to specify whether the data is related to a printer, scanner, or facsimile communication. In addition, it is necessary to delete and edit the header information added to the head of the control command. Therefore, there are great problems in terms of complexity of the control and a throughput.
Furthermore, the main control unit and printing unit included inside the facsimile apparatus are connected through one-way low-speed parallel communication dedicated to print data transfer. Therefore, in order for the main control unit to acquire printing information of the printing unit, it is necessary to provide a physical interface independent of the one-way parallel communication. This also causes the problems of an increased workload in designing products and complexity of the control. Further, if a printing unit capable of high-speed printing is used, transfer speed of print data from the main control unit to the printing unit is too slow to make the best use of the ability of the printing unit.
In addition, in integrating a reading/writing device from/to a detachable storage medium in the image processing apparatus, another different physical interface is necessary.